1. Field of the Invention
The present invention relates to imaging technology using an imaging apparatus and a flash device. More specifically, the present invention relates to an imaging apparatus, a flash device, and a flash control camera system, which configure a wireless communication system, and a synchronous imaging method and a program based on this wireless communication system.
2. Description of the Related Art
Conventionally, wireless communication systems using radio waves and light have been easier to use than wired communication systems, as there is no need to connect with a cable. However, wireless communication systems have been inferior in terms of communication reliability. For example, communication errors can occur when there is an obstruction in the communication pathway, interference caused by radio waves in the same frequency band, or incidence of strong light during communication. Therefore, communication reliability was ensured by providing an error correction mechanism or by re-transmitting a packet.
As a wireless communication system which is operated by synchronizing a plurality of devices, Japanese Patent Application Laid-Open No. 2000-89304 discusses a wireless flash system configured from a camera and a flash unit. This system uses light for wireless communication to realize a wireless multi-unit flash system which performs flash synchronous imaging at a high-speed shutter time of one several-hundredth of a second, and performs wireless centralized control of a plurality of flash units.
However, even in such a wireless flash system, the low reliability that wireless communication systems have is not totally resolved. For example, it is assumed that light communication is performed from a master flash unit to act as an emitting trigger for a slave flash unit. In this case, if another flash unit emits at the instant when the light communication acting as an emitting trigger is performed, the slave flash unit cannot distinguish the emitting trigger transmitted by the master flash unit from the another emitting, which can lead to unexpected emitting.